+ @SuppressWarnings("rawtypes")
+ protected static final class SymbolFunctionRequest extends ResourceRead<Function> {
+ protected static final Function CONST_NULL = new FunctionImpl1<Resource, String>() {
+ @Override
+ public String apply(Resource p0) {
+ return null;
+ }
+ };
+
+ public SymbolFunctionRequest(Resource entry) {
+ super(entry);
+ }
+
+ @Override
+ public Function perform(ReadGraph graph) throws DatabaseException {
+ DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
+
+ Function symbolFunction = (Function) graph.getPossibleRelatedValue2(resource, DN.HasSymbolFunction, resource);
+ if (symbolFunction == null)
+ symbolFunction = CONST_NULL;
+
+ return symbolFunction;
+ }
+ }
+